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116 lines
3.2 KiB
XML
116 lines
3.2 KiB
XML
<?xml version="1.0" encoding="iso-8859-1"?>
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<!DOCTYPE refentry PUBLIC "-//Samba-Team//DTD DocBook V4.2-Based Variant V1.0//EN" "http://www.samba.org/samba/DTD/samba-doc">
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<refentry id="vfs_readahead.8">
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<refmeta>
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<refentrytitle>vfs_readahead</refentrytitle>
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<manvolnum>8</manvolnum>
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<refmiscinfo class="source">Samba</refmiscinfo>
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<refmiscinfo class="manual">System Administration tools</refmiscinfo>
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<refmiscinfo class="version">3.2</refmiscinfo>
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</refmeta>
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<refnamediv>
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<refname>vfs_readahead</refname>
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<refpurpose>pre-load the kernel buffer cache</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<cmdsynopsis>
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<command>vfs objects = readahead</command>
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</cmdsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>DESCRIPTION</title>
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<para>This VFS module is part of the
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<citerefentry><refentrytitle>samba</refentrytitle>
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<manvolnum>7</manvolnum></citerefentry> suite.</para>
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<para>This <command>vfs_readahead</command> VFS module detects
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read requests at multiples of a given offset (hex 0x80000 by
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default) and then tells the kernel via either the readahead
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system call (on Linux) or the posix_fadvise system call to
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pre-fetch this data into the buffer cache.</para>
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<para>This module is useful for Windows Vista clients reading
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data using the Windows Explorer program, which asynchronously
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does multiple file read requests at offset boundaries of 0x80000
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bytes.</para>
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<para>The offset multiple used is given by the readahead:offset
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option, which defaults to 0x80000.</para>
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<para>The size of the disk read operations performed
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by <command>vfs_readahead</command> is determined by the
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readahead:length option. By default this is set to the
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same value as the readahead:offset option and if not
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set explicitly will use the current value of
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readahead:offset.</para>
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<para>This module is stackable.</para>
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</refsect1>
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<refsect1>
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<title>OPTIONS</title>
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<variablelist>
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<varlistentry>
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<term>readahead:offset = BYTES</term>
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<listitem>
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<para>The offset multiple that causes readahead to be
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requested of the kernel buffer cache.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term>readahead:length = BYTES</term>
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<listitem>
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<para>The number of bytes requested to be
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read into the kernel buffer cache on each
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readahead call.</para>
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</listitem>
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</varlistentry>
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<para>The following suffixes may be applied to BYTES:</para>
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<itemizedlist>
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<listitem><para><command>K</command> - BYTES is a number of kilobytes</para></listitem>
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<listitem><para><command>M</command> - BYTES is a number of megabytes</para></listitem>
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<listitem><para><command>G</command> - BYTES is a number of gigabytes</para></listitem>
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</itemizedlist>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>EXAMPLES</title>
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<programlisting>
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<smbconfsection name="[hypothetical]"/>
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<smbconfoption name="vfs objects">readahead</smbconfoption>
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</programlisting>
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</refsect1>
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<refsect1>
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<title>VERSION</title>
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<para>This man page is correct for version 3.0.25 of the Samba suite.
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</para>
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</refsect1>
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<refsect1>
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<title>AUTHOR</title>
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<para>The original Samba software and related utilities
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were created by Andrew Tridgell. Samba is now developed
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by the Samba Team as an Open Source project similar
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to the way the Linux kernel is developed.</para>
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</refsect1>
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</refentry>
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